Everything you need for the Microline TFC-435 Reverse Osmosis System Drinking Water System with RO membrane included. Replacement Filter Kit Includes: * STAGE 1 - 1x Sediment/Carbon Pre-Filter (S7028) - Replace every 6-12 months or as needed * STAGE 2 - 1x RO Membrane TFC 50 GPD (S1229RS) - Replace every 24 months * STAGE 3 - 1x Carbon GAC Post-Filter (S7025) - Replace every 6-12 months or as needed * STAGE 4 - 1x Inline Carbon GAC Post Filter (K2333-KK) - Replace every 6-12 months or as needed Filters may need to be replaced more often than indicated depending on incoming water contaminant levels and volume of water being treated.